Food packagers and retailers are being pressured to find ways of reducing packaging waste that ends up in landfill.
Reducing the material used in packaging is one way the industry is responding to the decreasing landfill capacity.
Trials funded by Waste & Resources Action Programme (WRAP) found that heat sealing film packaged salads reduced the amount of material required by up to 10 per cent compared to conventional crimping.
The project results, published this week, said that a 1mm wide weld also extended the shelf life of some salads from five days to eight, according to WRAP.
Extending the shelf life of food could also help to reduce the amount of food that finds its way to landfill sites.
A recent study found that up to one third of all food ends up uneaten.
The new seal also improves salad packaging appearance, which consumers found looked neater than crimped packaging in during the research, WRAP claims.
Andrew Parry, WRAP project manager, said new the technology could be applied across a wide range of product packs, including salad and snack bags.
"It reduces the amount of material used for each bag, can keep products fresher for longer, and so has the potential to divert a substantial amount of packaging material and food waste from landfill sites," he said.
The technology was developed by International Food Partners (IFP) and UK film sealing system firm, Ceetak and Tilmanstone Salads, a supplier to retailer Marks & Spencer.
M&S now intends to roll out heat sealed packaged salads in its stores by the end of the summer.
Helene Roberts, Head of Packaging for M&S, said the retailer was proud to be the first to use the new Integrity Seal technology.
"It enables us to reduce the amount of packaging we use, which helps us to lessen our impact on the envi ron ment as well as save on packaging cost," she said.
"It also benefits our customers as our salad packaging not only looks better but it helps the product stay fresher for a longer period."
A full technical report and case study on the trials is being produced by WRAP to demonstrate to other potential applications for the packaging seal.
The move by M&S follows its announcement in 2006 of a 100 point plan that aims to reduce the use of packaging in its stores by 25 per cent, and switch to renewable sources of packaging.
Other supermarkets, including Wal-Mart have also made pledges to reduce packaging and packaging waste.
WRAP is non-profit company set up in 2000, tasked to reduce all types of waste going into landfill.
In addition to cutting the amount of food waste, WRAP also has funds devoted to reducing the amount of packaging being thrown away.
The Courtauld Commitment is an agreement between 13 retailers and WRAP, and was developed in partnership with UK Government administrations.
Those who have made pledges include Asda, Boots, Budgens, the Co-operative Group, Londis, Iceland, Kwik Save, Marks & Spencer, Morrison's, Sainsbury's, Somerfield, Tesco and Waitrose.
The commitment calls for them to design out packaging waste growth by 2008, to deliver absolute reductions in packaging waste by March 2010 and to identify ways to tackle the problem of food waste.